Issac  Newton (born: 4 January, 1643 / died: 31 March, 1727)
Newton is best known for his Theory of Gravity,  but Newton had a non-mathematical, 'irrational' side. He spent an equal amount of time on a chronology of the scriptures, alchemy, occult medicine and biblical prophesies.   Historians have tended to ignore Newton's alchemical and religious interests, or simply denied that they had anything to do with his work in mathematics, physics, and astronomy.  Newton had however compiled at least one million words in several manuscripts on the subject of alchemy alone. 

Newton's interest in alchemy was integral to his approach to the natural world.   Newton was deeply influenced by the Neoplatonic and Hermetic movements of his day, which, for Newton, promised to open a window on the structure of matter and the hidden powers and energies of Nature.  He even tried to express and explain everything in the language of corpuscles, attractions and repulsions. 

In April 1669 Newton bought a furnace as well as a copy of the compilation of alchemical tracts, Theatrum Chemicum.  He also had a copy of the book entitled Secrets Reveal'd written by the mysterious Eirenaeus Philaslethes.  Newton heavily annotated the book, trying to show that alchemy mirrored God's labours during the creation and it referred to the operations of the Stoics' animating spirit in Nature.

Very possibly it was Newton's interest in solving the impossibly difficult problem of how passive, inert corpuscles organized themselves into living entities of the three kingdoms of Nature that drove him to explore the readily available printed texts and circulating manuscripts of alchemy.  Newton's motive, which was probably shared by many other seventeenth century figures, including Robert Boyle, was quite respectable.  Its purpose, ultimately, was theological.  A deeper understanding of God could well come from an understanding of the 'spirit', be it light, warmth, or a universal ether, which animated all things.